Compounds and combinations thereof for treating neurological and psychiatric conditions

ABSTRACT

This disclosure relates to administration of a combination of: 1) about 100-110 mg, about 104-106 mg, or about 105 mg of bupropion hydrochloride, or a molar equivalent amount of a free base form or another salt form of bupropion; and 2) about 40-50 mg, about 44-46 mg, or about 45 mg of dextromethorphan hydrobromide, or a molar equivalent amount of a free base form or another salt form of dextromethorphan in certain patient populations, such as patients having moderate renal impairment, patients receiving a concomitant strong CYP2D6 inhibitor, patients who are known CYP2D6 poor metabolizers, those in need of an NMDA antagonist that does not cause dissociation, and those at risk of QT prolongation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 18/173,291, filed Feb. 23, 2023; Which claims the benefit of U.S. Provisional Application No. 63/359,143, filed Jul. 7, 2022, U.S. Provisional Application No. 63/370,592, filed Aug. 5, 2022, U.S. Provisional Application No. 63/396,182, filed Aug. 8, 2022, U.S. Provisional Application No. 63/373,040, filed Aug. 19, 2022, and U.S. Provisional Application No. 63/401,541, filed Aug. 26, 2022; all of which are incorporated by reference in their entireties.

SUMMARY

This disclosure relates to administration of a combination of: 1) about 100-110 mg, about 104-106 mg, or about 105 mg of bupropion hydrochloride, or a molar equivalent amount of a free base form or another salt form of dextromethorphan; and 2) about 40-50 mg, about 44-46 mg, or about 45 mg of dextromethorphan hydrobromide, or a molar equivalent amount of a free base form or another salt form of dextromethorphan in certain patient populations.

Some embodiments include a method of treating major depressive disorder in a patient having moderate renal impairment, comprising administering a daily dose of: (i) about 105 mg of bupropion hydrochloride and (ii) about 45 mg of dextromethorphan hydrobromide to a human patient who has moderate renal impairment and is experiencing major depressive disorder.

Some embodiments include a method of treating major depressive disorder in a patient receiving a concomitant strong CYP2D6 inhibitor, comprising administering a daily dose of: (i) about 105 mg of bupropion hydrochloride and (ii) about 45 mg of dextromethorphan hydrobromide to a human patient who has major depressive disorder and is receiving concomitant treatment with a strong CYP2D6 inhibitor.

Some embodiments include a method of treating major depressive disorder in a patient who is a known CYP2D6 poor metabolizer, comprising administering a daily dose of: (i) about 105 mg of bupropion hydrochloride and (ii) about 45 mg of dextromethorphan hydrobromide to a human patient who is experiencing major depressive disorder and is known to be a CYP2D6 poor metabolizer.

Some embodiments include a method of using a non-competitive N-methyl D-aspartate (NMDA) receptor antagonist to treat major depressive disorder, comprising administering, no more than twice daily, a combination of 105 mg of bupropion hydrochloride and 45 mg of dextromethorphan hydrobromide to a human patient who is experiencing major depressive disorder, wherein the dextromethorphan acts as a non-competitive antagonist of the NMDA receptor and a sigma-1 receptor agonist, and the human patient does not experience dissociation.

Some embodiments include a method of treating major depressive disorder in a human patient at risk of QT prolongation, comprising administering, no more than twice daily, a combination of 105 mg of bupropion hydrochloride and 45 mg of dextromethorphan hydrobromide to a human patient who is experiencing major depressive disorder and is at risk of QT prolongation and torsades de pointes, wherein electrocardiographic evaluation of QT interval is not conducted on the human patient.

DETAILED DESCRIPTION

As mentioned above, this disclosure relates to administration of a combination of: 1) about 100-110 mg, about 104-106 mg, or about 105 mg of bupropion hydrochloride, or a molar equivalent amount of a free base form or another salt form of dextromethorphan; and 2) about 40-50 mg, about 44-46 mg, or about 45 mg of dextromethorphan hydrobromide, or a molar equivalent amount of a free base form or another salt form of dextromethorphan. This combination is referred to for convenience herein as the “subject combination.” In every instance where the subject combination is referred to herein, the combination of 105 mg of bupropion hydrochloride and 45 mg of dextromethorphan hydrobromide is specifically contemplated.

Dextromethorphan hydrobromide is a non-competitive NMDA receptor antagonist and A sigma-1 receptor agonist.

The chemical name of dextromethorphan hydrobromide is morphinan, 3-methoxy-17-methyl-, (9α, 13α, 14α), hydrobromide monohydrate. Dextromethorphan hydrobromide has the empirical formula C₁₈H₂₅NO·HBr·H₂O and a molecular weight of 370.33. The structural formula is:

Dextromethorphan hydrobromide powder is white or almost white, crystalline, and sparingly soluble in water.

Bupropion hydrochloride is an aminoketone and CYP450 2D6 inhibitor.

The chemical name of bupropion hydrochloride is: (±)-1-(3-chlorophenyl)-2-[(1,1-dimethylethyl)amino]-1-propanone hydrochloride. Bupropion hydrochloride has the empirical formula C₁₃H₁₈ClNO·HCl and a molecular weight of 276.2. The structural formula is:

Bupropion hydrochloride powder is white and highly soluble in water.

The subject combination may be contained in an oral dosage form, including a tablet, such as an extended-release tablet. In some embodiments, the subject combination is contained in a dosage form for oral administration and is available as round bilayer tablets.

In some embodiments, each tablet containing the subject combination contains 45 mg of dextromethorphan hydrobromide in an immediate-release formulation. In some embodiments, each tablet of the subject combination contains 105 mg of bupropion hydrochloride in an extended-release formulation. In some embodiments, each tablet of the subject combination contains 45 mg of dextromethorphan hydrobromide in an immediate-release formulation and 105 mg of bupropion hydrochloride in an extended-release formulation.

In some embodiments, a tablet containing the subject combination contains 1-cysteine hydrochloride monohydrate. In some embodiments, a tablet containing the subject combination contains carbomer homopolymer. In some embodiments, a tablet containing the subject combination contains microcrystalline cellulose. In some embodiments, a tablet containing the subject combination contains colloidal silicon dioxide. In some embodiments, a tablet containing the subject combination contains crospovidone. In some embodiments, a tablet containing the subject combination contains stearic acid. In some embodiments, a tablet containing the subject combination contains magnesium stearate.

In some embodiments, a tablet containing the subject combination contains the following inactive ingredients: 1-cysteine hydrochloride monohydrate, carbomer homopolymer, microcrystalline cellulose, colloidal silicon dioxide, crospovidone, stearic acid, and magnesium stearate.

In some embodiments, the starting dosage of the subject combination is 45 mg of dextromethorphan hydrobromide and 105 mg of bupropion hydrochloride in one tablet that is administered once daily in the morning. In some embodiments, after 3 days, the dosage is increased to one tablet (or one dosage form containing 45 mg of dextromethorphan hydrobromide and 105 mg of bupropion hydrochloride) twice daily, e.g., given at least 8 hours apart. In some embodiments, no more than two doses containing 45 mg of dextromethorphan hydrobromide and 105 mg of bupropion hydrochloride are administered in the same day.

The subject combination may be administered orally with or without food. In some embodiments, the tablets are swallowed whole, and not crushed, divided, or chewed.

Patients having renal impairment may require special dosing. In some embodiments, the recommended dosage of the subject combination for patients with moderate renal impairment (eGFR 30 to 59 mL/minute/1.73 m²) is one tablet (or one dosage form containing 45 mg of dextromethorphan hydrobromide and 105 mg of bupropion hydrochloride) once daily, such as one tablet or other oral dosage form daily in the morning.

Patients who are concomitantly using the subject combination with strong CYP2D6 inhibitors may require special dosing. Concomitant use of the subject combination with a strong CYP2D6 inhibitor increases plasma concentrations of dextromethorphan. In some embodiments, the recommended dosage of the subject combination when coadministered with a strong CYP2D6 inhibitor is one tablet (or one dosage form containing 45 mg of dextromethorphan hydrobromide and 105 mg of bupropion hydrochloride) once daily, such as one tablet or other oral dosage form daily in the morning. In some embodiments, the patients are monitored for adverse reactions potentially attributable to dextromethorphan, such as somnolence and dizziness.

Patients who are known CYP2D6 poor metabolizers (PMs) may require special dosing. In some embodiments, the recommended dosage for patients known to be poor CYP2D6 metabolizers is one tablet (or one dosage form containing 45 mg of dextromethorphan hydrobromide and 105 mg of bupropion hydrochloride) once daily, such as one tablet or other oral dosage form daily in the morning.

Special precautions may be required when switching a patient to or from a monoamine oxidase inhibitor (MAOI) antidepressant to the subject combination. In some embodiments, at least 14 days must elapse between discontinuation of an MAOI intended to treat depression and initiation of therapy with the subject combination. Conversely, in some embodiments, at least 14 days must be allowed after stopping the subject combination before starting an MAOI antidepressant.

In the subject combination, bupropion inhibits the metabolism of dextromethorphan via CYP2D6. Dextromethorphan, when co-administered with bupropion, displays nonlinear pharmacokinetics at steady state, with greater than dose-proportional changes in AUC and C_(max) for varying doses of dextromethorphan (30 to 60 mg) and less than dose-proportional changes for varying doses of bupropion (75 to 150 mg).

Steady state plasma concentrations of dextromethorphan and bupropion when given as the subject combination are achieved within 8 days. The accumulation ratios for dextromethorphan at steady state are about 20 and about 32, respectively based on C_(max) and AUC₀₋₁₂. The accumulation ratios for bupropion at steady state are 1.1 and 1.5, respectively based on C_(max) and AUC₀₋₁₂.

After administration of the subject combination, the median T_(max) of dextromethorphan is about 3 hours and the median T_(max) of bupropion is about 2 hours. The C_(max) of hydroxybupropion metabolite occurs approximately 3 hours post-dose and is approximately 14 times the peak level of bupropion. The AUC₀₋₁₂ hydroxybupropion is about 19 times that of bupropion. The C_(max) of the erythrohydroxybupropion and threohydroxybupropion metabolites occurs approximately 4 hours post-dose and is approximately equal to and about 5 times that of bupropion, respectively. The AUC₀₋₁₂ values of erythrohydroxybupropion and threohydroxybupropion are about 1.2 and about 7 times that of bupropion, respectively.

The subject combination can be taken with or without food. Dextromethorphan C_(max) and AUC₀₋₁₂ were unchanged and decreased by 14%, respectively, and bupropion C_(max) and AUC₀₋₁₂ were increased by 3% and 6%, respectively, when the subject combination was administered with food.

The plasma protein binding of dextromethorphan is approximately 60-70% and bupropion is 84%. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion; whereas the extent of protein binding of the threohydrobupropion metabolite is about half that seen with bupropion.

Following 8 days of administration of the subject combination in extensive metabolizers, the mean elimination half-life of dextromethorphan was increased approximately 3-fold to about 22 hours, as compared to dextromethorphan given without bupropion.

The mean elimination half-life of dextromethorphan and bupropion was 22 hours and 15 hours, respectively. The apparent elimination half-life of hydroxybupropion, erythrohydroxybuporpion and threohydroxybupropion metabolites were approximately 35, 44 and 33 hours, respectively.

Esketamine is a non-competitive NMDA receptor antagonist indicated, in conjunction with an oral antidepressant, for the treatment of treatment-resistant depression in adults.

Treatment of treatment-resistant depression carries a risk of dissociation. The label for esketamine states that because of the risks of sedation and dissociation, patients must be monitored for at least 2 hours at each treatment session, followed by an assessment to determine when the patient is considered clinically stable and ready to leave the healthcare setting.

Dissociation includes: delusional perception; depersonalization/derealization disorder; derealization; diplopia; dissociation; dysesthesia; feeling cold; feeling hot; feeling of body temperature change; hallucination; hallucination, auditory; hallucination, visual; hyperacusis; illusion; ocular discomfort; oral dysesthesia; paranesthesia; paranesthesia oral; pharyngeal paranesthesia; photophobia; time perception altered; tinnitus; vision blurred; visual impairment.

The subject combination is a combination of dextromethorphan, a non-competitive N-methyl D-aspartate (NDMA) receptor antagonist and sigma-1 receptor agonist, and bupropion, an aminoketone and CYP450 2D6 inhibitor, indicated for the treatment of major depressive disorder (MDD) in adults. Unlike esketamine, the subject combination can be administered as a without dissociation or dissociative events. In some embodiments, the patient is not monitored for dissociation after the subject combination is administered.

The following information includes the kinds of dissociative and other effects that may be avoided with the combination of dextromethorphan and bupropion.

In clinical trials, 48% to 61% of esketamine-treated patients developed sedation based on the Modified Observer's Assessment of Alertness/Sedation scale (MOAA/S), and 0.3% to 0.4% of esketamine-treated patients experienced loss of consciousness (MOAA/S score of 0). For a combination of dextromethorphan and bupropion, NMDA receptor antagonism may be achieved without a significant risk of sedation.

Because of the possibility of delayed or prolonged sedation, patients receiving esketamine must be monitored by a healthcare provider for at least 2 hours at each treatment session, followed by an assessment to determine when the patient is considered clinically stable and ready to leave the healthcare setting. No such monitoring is required for the treatment of the combination of dextromethorphan and bupropion.

Esketamine-treated patients must be closely monitored for sedation with concomitant use of ESKETAMINE with CNS depressants. No such monitoring is required for the treatment of the combination of dextromethorphan and bupropion.

Esketamine is available only through a restricted program under a REMS. No such restrictions are required for the combination of dextromethorphan and bupropion.

The most common psychological effects of esketamine were dissociative or perceptual changes (including distortion of time, space and illusions), derealization and depersonalization (61% to 84% of esketamine-treated patients developed dissociative or perceptual changes based on the Clinician-Administered Dissociative States Scale). Given its potential to induce dissociative effects, patients with psychosis must be carefully assessed before administering esketamine. No such assessment is required for the treatment of the combination of dextromethorphan. Treatment with esketamine should be initiated only if the benefit outweighs the risk. No such restriction is required with the treatment of the combination of dextromethorphan and bupropion.

Because of the risks of dissociation, patients receiving esketamine must be monitored by a healthcare provider for at least 2 hours at each treatment session, followed by an assessment to determine when the patient is considered clinically stable and ready to leave the healthcare setting. No such monitoring, assessment, or restriction is required for the treatment of the combination of dextromethorphan and bupropion. Esketamine is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS). No such restrictions are required for the combination of dextromethorphan and bupropion.

Dissociation includes: delusional perception (including distortion of space and time, and illusions); depersonalization/derealization disorder; derealization; diplopia; dissociation; dysesthesia; feeling cold; feeling hot; feeling of body temperature change; hallucination; hallucination, auditory; hallucination, visual; hallucinations, mixed; hyperacusis; illusion; ocular discomfort; oral dysesthesia; paresthesia; paresthesia oral; pharyngeal paresthesia; photophobia; time perception altered; tinnitus; vision blurred; and visual impairment.

Esketamine is a Schedule Ill controlled substance (CIII), and may be subject to abuse and diversion. The combination of dextromethorphan and bupropion is not a controlled substance. Each patient's risk for abuse or misuse must be assessed prior to prescribing and all patients receiving esketamine must be monitored for the development of these behaviors or conditions, including drug-seeking behavior, while on therapy. No such monitoring or assessment is required for the treatment of the combination of dextromethorphan and bupropion.

Esketamine is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) and is called the esketamine REMS because of the risks of serious adverse outcomes from sedation, dissociation, and abuse and misuse. No such restrictions are required for the combination of dextromethorphan and bupropion.

Important requirements of the esketamine REMS include the following:

-   -   Healthcare settings must be certified in the program and ensure         that esketamine is:         -   Only dispensed and administered in healthcare settings.         -   Patients treated in outpatient settings (e.g., medical             offices and clinics) must be enrolled in the program.         -   Administered by patients under the direct observation of a             healthcare provider and that patients are monitored by a             healthcare provider for at least 2 hours after             administration of esketamine.             None of these requirements apply to the combination of             dextromethorphan and bupropion.

Esketamine was evaluated for safety in 262 adults for the treatment of depressive symptoms in adults with major depressive disorder (MDD) with acute suicidal ideation or behavior from two Phase 3 studies (Study 3 and Study 4) and one Phase 2 study.

Sedation was evaluated by adverse event reports and the Modified Observer's Assessment of Alertness/Sedation (MOAA/S). In the MOAA/S, a score of 5 means “responds readily to name spoken in normal tone;” a score of 0 means “no response after painful trapezius squeeze;” a score of 4 means “lethargic response to name spoken in normal tone;” a score of 3 means “responds only after name is spoken loudly and/or repeatedly;” a score of 2 means “responds only after mild prodding or shaking;” and a score of 1 means “does not respond to mild prodding or shaking.” Any decrease in MOAA/S score from pre-dose is considered to indicate the presence of sedation, and such a decrease occurred in a higher number of patients on esketamine than placebo during the short-term Treatment Resistant Depression (TRD) studies. Dose-related increases in the incidence of sedation (MOAA/S score<5) were observed in a fixed-dose TRD study. Table 1 presents the incidence of sedation (MOAA/S score<5) in a fixed-dose study with adult patients<65 years of age with TRD and a flexible-dose study with patients>65 years of age with TRD.

TABLE 1 Incidence of Sedation (MOAA/S Score <5) in Double-Blind, Randomized, Placebo-Controlled Studies (Fixed-Dose Study with Adult Patients <65 Years of Age with treatment-resistant depression and Flexible-Dose Study with Patients ≥65 Years of Age with treatment-resistant depression) Patients <65 years Patients ≥65 years SPRAVATO + SPRAVATO + Placebo + Oral AD Placebo + Oral AD Oral AD 56 mg 84 mg Oral AD 28 to 84 mg Number of patients* N = 112 N = 114 N = 114 N = 63 N = 72 Sedation (MOAA/S 11% 50% 61% 19% 49% score <5) *Patients who were evaluated with MOAA/S

In studies for the treatment of depressive symptoms in adults with MDD with acute suicidal ideation or behavior, there was a higher incidence of sedation (MOAA/S score<5) in patients treated with esketamine plus oral antidepressant compared to patients treated with placebo plus oral antidepressant (AD), similar to the treatment-resistant depression study results in Table 1.

Dissociation/Perceptual Changes

Esketamine can cause dissociative symptoms (including derealization and depersonalization) and perceptual changes (including distortion of time and space, and illusions). In clinical trials, dissociation was transient and occurred on the day of dosing. Dissociation was evaluated by adverse event reports and the Clinician-Administered Dissociative States Scale (CADSS). A CADSS total score of more than 4 indicates the presence of dissociative symptoms, and such an increase to a score of 4 or more occurred in a higher number of patients on esketamine compared to placebo during the short-term treatment-resistant depression studies. Dose-related increases in the incidence of dissociative symptoms (CADSS total score>4 and change>0) were observed in a fixed-dose treatment-resistant depression study. Table 2 presents the incidence of dissociation (CADSS total score>4 and change>0) in a fixed-dose study with adult patients<65 years of age with treatment-resistant depression and a flexible-dose study with patients>65 years of age with treatment-resistant depression.

TABLE 2 Incidence of Dissociation (CADSS Total Score >4 and Change >0) in Double-Blind, Randomized, Placebo-Controlled Studies (Fixed-Dose Study with Adult Patients <65 Years of Age with treatment-resistant depression and Flexible-Dose Study with Patients ≥65 Years of Age with treatment-resistant depression) Patients <65 years Patients ≥65 years ESKETAMINE + ESKETAMINE + Placebo + Oral AD Placebo + Oral AD Oral AD 56 mg 84 mg Oral AD 28 to 84 mg Number of patients* N = 113 N = 113 N = 116 N = 65 N = 72 CADSS total score >4 and 5% 61% 69% 12% 75% change >0 *Number of patients who were evaluated with CADSS

In studies for the treatment of depressive symptoms in adults with MDD with acute suicidal ideation or behavior, patients treated with esketamine plus oral AD also demonstrated a higher number (84%) with dissociation (CADSS total score>4 and change>0) compared to patients treated with placebo plus oral AD (16%).

Because the subject combination can be administered without dissociation or dissociative events, its risk of abuse is reduced as compared to esketamine. Abuse is the intentional, non-therapeutic use of a drug, even once, for its desirable psychological or physiological effects. Clinical studies with the combination of dextromethorphan and bupropion did not reveal drug-seeking behavior, although these observations were not systematic. Therefore, patients with a history of drug abuse may be observed closely for signs of the subject combination of dextromethorphan and bupropion misuse or abuse (e.g., development of tolerance, increases in dose, drug-seeking behavior). Unlike the combination of quinidine and dextromethorphan, at a dose of a combination of 105 mg of bupropion hydrochloride and 45 mg of dextromethorphan hydrobromide given twice a day, the subject combination does not prolong the QT interval to any clinically relevant extent. Thus, for a human patient who is experiencing major depressive disorder and is at risk of QT prolongation and torsades de pointes, electrocardiographic evaluation of QT interval is not typically conducted on the human patient.

The subject combination may be used for adjunctive treatment of major depressive disorder or depression.

In addition to major depressive disorder, the subject combination may be used to treat other diseases in conditions in the patient populations or circumstances described herein. For example, the subject combination may be used to treat pain or a neurological disorder. Examples of neurological disorders that may be treated with the subject combination include, but are not limited to: affective disorders, psychiatric disorders, cerebral function disorders, movement disorders, dementias, motor neuron diseases, neurodegenerative diseases, seizure disorders, and headaches.

Affective disorders that may be treated by the subject combination include, but are not limited to, depression, major depression, treatment resistant depression, treatment resistant bipolar depression, bipolar disorders including cyclothymia, seasonal affective disorder, mood disorders, chronic depression (dysthymia), psychotic depression, postpartum depression, premenstrual dysphoric disorder (PMDD), situational depression, atypical depression, mania, anxiety disorders, attention deficit disorder (ADD), attention deficit disorder with hyperactivity (ADDH), and attention deficit/hyperactivity disorder (AD/HD), bipolar and manic conditions, obsessive-compulsive disorder, bulimia, obesity or weight-gain, narcolepsy, chronic fatigue syndrome, premenstrual syndrome, substance addiction or abuse, nicotine addiction, psycho-sexual dysfunction, pseudobulbar affect, and emotional lability.

Depression may be manifested by depressive symptoms. These symptoms may include psychological changes such as changes in mood, feelings of intense sadness, despair, mental slowing, loss of concentration, pessimistic worry, agitation, anxiety, irritability, guilt, anger, feelings of worthlessness, reckless behavior, suicidal thoughts, or attempts, and/or self-deprecation. Physical symptoms of depression may include insomnia, anorexia, appetite loss, weight loss, weight gain, decreased energy and libido, fatigue, restlessness, aches, pains, headaches, cramps, digestive issues, and/or abnormal hormonal circadian rhythms.

Psychiatric disorders that may be treated by the subject combination, include, but are not limited to, anxiety disorders, including but not limited to, phobias, generalized anxiety disorder, social anxiety disorder, panic disorder, agoraphobia, obsessive-compulsive disorder, and post-traumatic stress disorder (PTSD); mania, manic depressive illness, hypomania, unipolar depression, depression, stress disorders, somatoform disorders, personality disorders, psychosis, schizophrenia, delusional disorder, schizoaffective disorder, schizotypy, aggression, aggression in Alzheimer's disease, agitation, and agitation in Alzheimer's disease. Alzheimer's disease may also be referred to as dementia of the Alzheimer's type. Other neurobehavioral symptoms of Alzheimer's disease that may be treated include disinhibition and apathy.

Agitation in Alzheimer's disease occurs as the disease progresses. Agitation may present itself as inappropriate verbal, emotional, and/or physical behaviors. Inappropriate behaviors may include, but are not limited to, incoherent babbling, inappropriate emotional response, demands for attention, threats, irritability, frustration, screaming, repetitive questions, mood swings, cursing, abusive language, physical outbursts, emotional distress, restlessness, shredding, sleeping disturbances, delusions, hallucinations, pacing, wandering, searching, rummaging, repetitive body motions, hoarding, shadowing, hitting, scratching, biting, combativeness, hyperactivity, and/or kicking.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, and behavioral and psychological symptoms including agitation. AD is the most common form of dementia and afflicts an estimated 6 million individuals in the United States, a number that is anticipated to increase to approximately 14 million by 2050. Agitation is reported in up to 70% of patients with AD and is characterized by emotional distress, aggressive behaviors, disruptive irritability, and disinhibition. Managing agitation is a priority in AD. Agitation in patients with AD has been associated with increased caregiver burden, decreased functioning, accelerated cognitive decline, earlier nursing home placement, and increased mortality. There are currently no therapies approved by the FDA for the treatment of agitation in patients with AD.

Neurobehavioral symptoms have been known to appear during dementia and may be treated by the combination. Caregivers or families may feel more overwhelmed by patients' behavioral/psychological symptoms than by their cognitive impairment. Common forms of the syndrome are Alzheimer's disease, vascular dementia, dementia with Lewy bodies (abnormal aggregates of protein that develop inside nerve cells), and a group of diseases that contribute to frontotemporal dementia (degeneration of the frontal lobe of the brain). The symptoms that dementia patients have are similar to those of psychiatric disorders, but some are slightly different from each other. Neurobehavioral symptoms associated with dementia include depression, apathy, agitation, disinhibition, hallucinations, delusions, psychosis, impulsiveness, aggressiveness, compulsion, excessive sex drive, and personality disorders. Neurobehavioral symptoms such as disinhibition may also be found in other conditions such as traumatic brain injury.

Agitation in patients with Alzheimer's disease may be assessed using the Cohen Mansfield Agitation Inventory or CMAI. The CMAI assesses various behaviors including, Hitting (including self), Kicking, Grabbing onto people, Pushing, Throwing things, Biting, Scratching, Spitting, Hurting self or others, Tearing things or destroying property, Making physical sexual advances, Pacing, aimless wandering, Inappropriate dress or disrobing, Trying to get to a different place, Intentional falling, Eating/drinking inappropriate substances, Handling things inappropriately, Hiding things, Hoarding things, Performing repetitive mannerisms, General restlessness, Screaming, Making verbal sexual advances, Cursing or verbal aggression, Repetitive sentences or questions, Strange noises (weird laughter or crying), Complaining, Negativism, Constant unwarranted request for attention or help.

Schizophrenia may be treated by the combination including positive symptoms and/or negative symptoms of schizophrenia, or residual symptoms of schizophrenia. Other conditions that may treated include intermittent explosive disorder.

Cerebral function disorders that may be treated by the subject combination include, but are not limited to, disorders involving intellectual deficits such as senile dementia, Alzheimer's type dementia, memory loss, amnesia/amnestic syndrome, epilepsy, disturbances of consciousness, coma, lowering of attention, speech disorders, voice spasms, Parkinson's disease, Lennox-Gastaut syndrome, autism, hyperkinetic syndrome, and schizophrenia. Cerebral function disorders also include disorders caused by cerebrovascular diseases including, but not limited to, stroke, cerebral infarction, cerebral bleeding, cerebral arteriosclerosis, cerebral venous thrombosis, head injuries, and the like where symptoms include disturbance of consciousness, senile dementia, coma, lowering of attention, and speech disorders.

Substance addiction abuse that may be treated by the subject combination includes, but is not limited to, drug dependence, addiction to cocaine, psychostimulants (e.g., crack, cocaine, speed, meth), nicotine, alcohol, opioids, anxiolytic and hypnotic drugs, cannabis (marijuana), amphetamines, hallucinogens, phencyclidine, volatile solvents, and volatile nitrites. Nicotine addiction includes nicotine addiction of all known forms, such as smoking cigarettes, cigars and/or pipes, e-cigarettes or vaping, and addiction to chewing tobacco.

Movement disorders that may be treated by the subject combination include, but are not limited to, akathisia, akinesia, associated movements, athetosis, ataxia, ballismus, hemiballismus, bradykinesia, cerebral palsy, chorea, Huntington's disease, Huntington's disease chorea, rheumatic chorea, Sydenham's chorea, dyskinesia, tardive dyskinesia, dystonia, blepharospasm, spasmodic torticollis, dopamine-responsive dystonia, Parkinson's disease, restless legs syndrome (RLS), tremor, essential tremor, and Tourette's syndrome, and Wilson's disease.

Dementias that may be treated by the subject combination include, but are not limited to, Alzheimer's disease, Parkinson's disease, vascular dementia, dementia with Lewy bodies, mixed dementia, fronto-temporal dementia, Creutzfeldt-Jakob disease, normal pressure hydrocephalus, Huntington's disease, Wernicke-Korsakoff Syndrome, and Pick's disease.

Motor neuron diseases that may be treated by the subject combination include, but are not limited to, amyotrophic lateral sclerosis (ALS), progressive bulbar palsy, primary lateral sclerosis (PLS), progressive muscular atrophy, post-polio syndrome (PPS), spinal muscular atrophy (SMA), spinal motor atrophies, Tay-Sach's disease, Sandoff disease, and hereditary spastic paraplegia.

Neurodegenerative diseases that may be treated the subject combination include, but are not limited to, Alzheimer's disease, prion-related diseases, cerebellar ataxia, spinocerebellar ataxia (SCA), spinal muscular atrophy (SMA), bulbar muscular atrophy, Friedrich's ataxia, Huntington's disease, Lewy body disease, Parkinson's disease, amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), multiple sclerosis (MS), multiple system atrophy, Shy-Drager syndrome, corticobasal degeneration, progressive supranuclear palsy, Wilson's disease, Menkes disease, adrenoleukodystrophy, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), muscular dystrophies, Charcot-Marie-Tooth disease (CMT), familial spastic paraparesis, neurofibromatosis, olivopontine cerebellar atrophy or degeneration, striatonigral degeneration, Guillain-Barre syndrome, and spastic paraplesia.

Seizure disorders that may be treated by the subject combination include, but are not limited to, epileptic seizures, nonepileptic seizures, epilepsy, febrile seizures; partial seizures including, but not limited to, simple partial seizures, Jacksonian seizures, complex partial seizures, and epilepsia partialis continua; generalized seizures including, but not limited to, generalized tonic-clonic seizures, absence seizures, atonic seizures, myoclonic seizures, juvenile myoclonic seizures, and infantile spasms; and status epilepticus.

Types of headaches that may be treated by the subject combination include, but are not limited to, migraine, tension, and cluster headaches.

Other neurological disorders that may be treated by the subject combination include, Rett Syndrome, autism, tinnitus, disturbances of consciousness disorders, sexual dysfunction, intractable coughing, narcolepsy, cataplexy; voice disorders due to uncontrolled laryngeal muscle spasms, including, but not limited to, abductor spasmodic dysphonia, adductor spasmodic dysphonia, muscular tension dysphonia, and vocal tremor; diabetic neuropathy, chemotherapy-induced neurotoxicity, such as methotrexate neurotoxicity; incontinence including, but not limited, stress urinary incontinence, urge urinary incontinence, and fecal incontinence; and erectile dysfunction.

In some embodiments, the subject combination may be used to treat pain, joint pain, pain associated with sickle cell disease, pseudobulbar affect, depression (including treatment resistant depression), disorders related to memory and cognition, schizophrenia, Parkinson's disease, amyotrophic lateral sclerosis (ALS), Rhett's syndrome, seizures, cough (including chronic cough), etc.

In some embodiments, the subject combination may be administered orally to relieve musculoskeletal pain including low back pain, and pain associated with rheumatoid arthritis, juvenile rheumatoid arthritis, osteoarthritis, erosive osteoarthritis, sero-negative (non-rheumatoid) arthropathies, non-articular rheumatism, peri-articular disorders, axial spondyloarthritis including ankylosing spondylitis, Paget's disease, fibrous dysplasia, SAPHO syndrome, transient osteoarthritis of the hip, vertebral crush fractures, osteoporosis, etc.

In some embodiments, the subject combination may be administered to relieve inflammatory pain including musculoskeletal pain, arthritis pain, and complex regional pain syndrome.

Arthritis refers to inflammatory joint diseases that can be associated with pain. Examples of arthritis pain include pain associated with osteoarthritis, erosive osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, sero-negative (non-rheumatoid) arthropathies, non-articular rheumatism, peri-articular disorders, neuropathic arthropathies including Charcot's foot, axial spondyloarthritis including ankylosing spondylitis, and SAPHO syndrome.

In some embodiments, the subject combination is used to treat chronic musculoskeletal pain.

In some embodiments, the subject composition may be administered to relieve complex regional pain syndrome, such as complex regional pain syndrome type I (CRPS-I), complex regional pain syndrome type II (CRPS-II), CRPS-NOS, or another type of CRPS. CRPS is a type of inflammatory pain. CRPS can also have a neuropathic component. Complex regional pain syndrome is a debilitating pain syndrome. It is characterized by severe pain in a limb that can be accompanied by edema, and autonomic, motor, and sensory changes.

In some embodiments, the subject composition may be administered orally to relieve neuropathic pain.

Examples of neuropathic pain include pain due to diabetic peripheral neuropathy or diabetic peripheral neuropathic pain, post-herpetic neuralgia, trigeminal neuralgia, monoradiculopathies, phantom limb pain, central pain, pain due to multiple sclerosis, etc. Other causes of neuropathic pain include cancer-related pain, lumbar nerve root compression, spinal cord injury, post-stroke pain, central multiple sclerosis pain, HIV-associated neuropathy, and radio- or chemo-therapy associated neuropathy, etc.

In some embodiments, the subject composition may be administered to relieve fibromyalgia.

The term “treating”, or “treatment” includes the diagnosis, cure, mitigation, treatment, or prevention of disease in man or other animals, or any activity that otherwise affects the structure or any function of the body of man or other animals.

A subject combination may be used to treat any disease or condition identified as treatable by the combination of bupropion and dextromethorphan in any of the following U.S. Pat. Nos. 8,569,328, 9,168,234, 9,198,905, 9,205,083, 9,238,032, 9,278,095, 9,314,462, 9,370,513, 9,375,429, 9,408,815, 9,421,176, 9,457,023, 9,457,025, 9,474,731, 9,486,450, 9,700,528, 9,700,553, 9,707,191, 9,763,932, 9,861,595, 9,867,819, 9,968,568, 10,058,518, 10,064,857, 10,080,727, 10,092,560, 10,092,561, 10,105,327, 10,105,361, 10,251,879, 10,463,634, 10,512,643, 10,548,857, 10,596,167, 10,772,850, 10,780,064, 10,780,066, 10,786,469, 10,786,496, 10,799,497, 10,806,710, 10,864,209, 10,874,663, 10,874,664, 10,874,665, 10,881,624, 10,881,657, 10,894,046, 10,894,047, 10,898,453, all of which are incorporated by reference herein in their entireties for their disclosure of diseases that may be treated by a combination of bupropion and dextromethorphan, including specific embodiments and combinations described therein.

The following U.S. Provisional applications are also incorporated by reference herein in their entireties: Ser. No. 63/359,143, filed Jul. 7, 2022, Ser. No. 63/370,592, filed Aug. 5, 2022, Ser. No. 63/396,182, filed Aug. 8, 2022, Ser. No. 63/373,040, filed Aug. 19, 2022, and Ser. No. 63/401,541, filed Aug. 26, 2022.

Example 1

In a study of the subject combination in 7 subjects with moderate (GFR 30-60 mL/min) renal impairment compared to 6 matched controls with normal renal function (matched in gender, age, and weight range to impaired subjects), both dextromethorphan and bupropion exposures increased by approximately 2-fold and clearances were reduced by 50%.

Example 2

Approximately 7 to 10% of Caucasians and 3 to 8% of African Americans lack the capacity to metabolize CYP2D6 substrates and are classified as poor metabolizers. In 3 poor metabolizers the pharmacokinetics of the subject combination resulted in an approximate 3-fold and 3.4-fold increase in dextromethorphan C_(max) and AUC₀₋₁₂, respectively, compared to extensive metabolizers. An exploration of steady state pharmacokinetic data in 12 poor metabolizers treated with the subject combination in efficacy trials showed plasma concentrations of dextromethorphan that were generally higher than exposures for non-poor metabolizers.

Example 3

Co-administration of the SSRI paroxetine and the subject combination was studied in 29 healthy volunteers. Paroxetine increased the overall exposure of dextromethorphan by 2.5-fold and had no effect on bupropion. The overall exposure of paroxetine was increased by 1.2-fold when co-administered with the subject combination. Based on these results, when the subject combination is prescribed with drugs that inhibit CYP2D6, the subject combination should be dosed once daily. Use caution when administering the subject combination in conjunction with drugs which are extensively metabolized via CYP2D6.

Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as amounts, percentage, and so forth used in the specification and claims are to be understood in all instances as indicating both the exact values as shown and as being modified by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Use of the term “comprising” or “comprises” herein also contemplates that use of “consisting essentially of,” “consists essentially of,” “consisting of,” or “consists of” in its place.

Affirmative recitation of an element anywhere herein should be understood to contemplate both including and excluding that element.

The terms “a,” “an,” “the” and similar referents used in the context of describing the embodiments (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of any claim. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the claims.

Groupings of alternative elements or embodiments disclosed herein are not to be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from a group, for reasons of convenience and/or to expedite prosecution. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified thus fulfilling the written description of all Markush groups if used in the appended claims.

Certain embodiments are described herein, including the best mode known to the inventors for carrying out the claimed embodiments. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the claimed embodiments to be practiced otherwise than specifically described herein. Accordingly, the claims include all modifications and equivalents of the subject matter recited in the claims as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is contemplated unless otherwise indicated herein or otherwise clearly contradicted by context.

In closing, it is to be understood that the embodiments disclosed herein are illustrative of the principles of the claims. Other modifications that may be employed are within the scope of the claims. Thus, by way of example, but not of limitation, alternative embodiments may be utilized in accordance with the teachings herein. Accordingly, the claims are not limited to embodiments precisely as shown and described. 

1. A method of treating depression in a human patient using an N-methyl D-aspartate (NMDA) receptor antagonist comprising, administering a combination of the NMDA receptor antagonist and a second agent that increases the plasma levels of the NMDA receptor antagonist to the human patient, wherein the NMDA receptor antagonist is dextromethorphan in the free base form at a dose of about 33 mg twice daily, or a molar equivalent amount of a salt form of dextromethorphan, and the second agent is bupropion in the free base form at a dose of 91 mg twice daily, or a molar equivalent amount of a salt form of bupropion, wherein the human patient experiences a reduction in depression symptoms after one week of treatment that is greater than what would be achieved with a placebo, wherein the human patient has a history of drug abuse, and wherein the human patient does not experience depersonalization or derealization disorder.
 2. The method of claim 1, wherein the dextromethorphan acts as an uncompetitive antagonist of the NMDA receptor and a sigma-1 receptor agonist.
 3. The method of claim 1, wherein the combination comprises 45 mg of dextromethorphan hydrobromide and 105 mg of bupropion hydrochloride.
 4. The method of claim 1, wherein the dextromethorphan is in an immediate-release formulation.
 5. The method of claim 1, wherein the bupropion is in an extended-release formulation.
 6. The method of claim 1, wherein the combination of the dextromethorphan and the bupropion are administered in a dosage form that further comprises an L-cysteine.
 7. The method of claim 1, wherein the human patient is monitored for any indication of clinical worsening.
 8. The method of claim 1, wherein the human patient is monitored for any emergence of suicidal thoughts or behaviors.
 9. A method of treating depression in a human patient using an N-methyl D-aspartate (NMDA) receptor antagonist comprising, administering a combination of the NMDA receptor antagonist and a second agent that increases the plasma levels of the NMDA receptor antagonist to the human patient, wherein the NMDA receptor antagonist is dextromethorphan in the free base form at a dose of about 33 mg twice daily, or a molar equivalent amount of a salt form of dextromethorphan, and the second agent is bupropion in the free base form at a dose of 91 mg twice daily, or a molar equivalent amount of a salt form of bupropion, wherein the human patient experiences a reduction in depression symptoms after one week of treatment that is greater than what would be achieved with a placebo, wherein the human patient has a history of drug abuse, and wherein the human patient does not experience sedation.
 10. The method of claim 9, wherein the dextromethorphan acts as an uncompetitive antagonist of the NMDA receptor and a sigma-1 receptor agonist.
 11. The method of claim 9, wherein the combination comprises 45 mg of dextromethorphan hydrobromide and 105 mg of bupropion hydrochloride.
 12. The method of claim 9, wherein the dextromethorphan is in an immediate-release formulation.
 13. The method of claim 9, wherein the bupropion is in an extended-release formulation.
 14. The method of claim 9, wherein the combination of the dextromethorphan and the bupropion are administered in a dosage form that further comprises an L-cysteine.
 15. The method of claim 9, wherein the human patient is monitored for any indication of clinical worsening.
 16. The method of claim 9, wherein the human patient is monitored for any emergence of suicidal thoughts or behaviors.
 17. A method of treating depression in a human patient using an N-methyl D-aspartate (NMDA) receptor antagonist comprising, administering a combination of the NMDA receptor antagonist and a second agent that increases the plasma levels of the NMDA receptor antagonist to the human patient, wherein the NMDA receptor antagonist is dextromethorphan in the free base form at a dose of about 33 mg twice daily, or a molar equivalent amount of a salt form of dextromethorphan, and the second agent is bupropion in the free base form at a dose of 91 mg twice daily, or a molar equivalent amount of a salt form of bupropion, wherein the human patient experiences a reduction in depression symptoms after one week of treatment that is greater than what would be achieved with a placebo, wherein the human patient has a history of drug abuse, and wherein the human patient does not experience a clinically significant prolongation of the QT interval.
 18. The method of claim 17, wherein the dextromethorphan acts as an uncompetitive antagonist of the NMDA receptor and a sigma-1 receptor agonist.
 19. The method of claim 17, wherein the combination comprises 45 mg of dextromethorphan hydrobromide and 105 mg of bupropion hydrochloride.
 20. The method of claim 17, wherein the dextromethorphan is in an immediate-release formulation.
 21. The method of claim 17, wherein the bupropion is in an extended-release formulation.
 22. The method of claim 17, wherein the combination of the dextromethorphan and the bupropion are administered in a dosage form that further comprises an L-cysteine.
 23. The method of claim 17, wherein the human patient is monitored for any indication of clinical worsening.
 24. The method of claim 17, wherein the human patient is monitored for any emergence of suicidal thoughts or behaviors. 